1. Field of the Invention
This invention relates generally to a chair having an adjustable back-support and especially to a back-support wherein movement to a reclined position is resiliently opposed.
In particular, the chair of this invention concerns a back-support that is user responsive and anatomically compliant.
2. Background Art
Current seating designs for office furniture, such as task chairs, have incorporated multiple positional adjustment features for providing user comfort. With regard to back-support, angular adjustability relative to the seat is commonly effected by a lever control tilt mechanism. The tilt mechanism frequently operates independently and/or in combination with a seat adjustment; other features provide for the tilt function to be locked-out, free-floating and/or set in a fixed angular orientation.
The tilt mechanism conventionally has a pivot point located below the seat and directly above the center of the chair base. The pivot point can also be located slightly ahead of the center so as to allow the chair occupant to recline at a slightly more relaxed angle than with the previously mentioned center-tilt. The pivot point can also be located near the front edge of the chair so as to allow the chair occupant to keep feet flat on the floor while the seat back is reclined. A further design, as shown in U.S. Pat. No. 4,157,203, places the pivot point or tilt axis above the seat at a location corresponding to about the middle of the back of the chair occupant.
A problem inherent in the aforementioned tilt mechanisms, is that the pivot point is not aligned with the hips of the chair occupant but rather is located approximately 6 to 8 inches below the hips of the occupant. Consequently, there is relative movement at the interface between the surfaces of the back-support and the occupant resulting in a frictional engagement of the occupants' clothing such that the chair occupant experiences an unpleasant "tugging" or "pull" upon the garment.
Although, the chair design as shown in U.S. Pat. No. 5,725,276 has a pivot point that is positioned above the seat and is intended to obviate this problem, the tilt mechanism is somewhat complex and it is relatively expensive to manufacture.
The back-support of the present invention includes a pivot point locus for tiltable movement that is more consistent with the chair occupant's anatomical positional change when reclining than with conventional tilt back chairs.